The Okanagan (/ˌoʊkəˈnɑːɡən/ OH-kə-NAH-gən), also called the Okanagan Valley and sometimes the Okanagan Country, is a region in the Canadian province of British Columbia defined by the basin of Okanagan Lake and the Canadian portion of the Okanagan River. It is part of the Okanagan Country, extending into the United States as Okanogan County in north-central Washington. According to the 2016 Canadian census, the region's population is 362,258. The largest populated cities are Kelowna, Penticton, Vernon, and West Kelowna.

The region is known for its sunny climate, dry landscapes, lakeshore communities, and particular lifestyle. The economy is retirement- and commercial-recreation-based, with outdoor activities such as boating and watersports, skiing, and hiking. Agriculture has been focused primarily on fruit orchards, with a recent shift in focus to vineyards and wine.

The region stretches northwards via the Spallumcheen Valley to Sicamous in the Shuswap Country, and reaches south of the Canada–United States border, where it continues as Okanogan County. The Okanagan as a region is sometimes described as including the Boundary, Similkameen, and Shuswap regions, though this is because of proximity and historic and commercial ties with those areas.

The name is derived from the Okanagan-language place name ukʷnaqín. An alternative explanation from Washington is ‘People living where you can see the top’, ostensibly of Chopaka Peak in the Lower Similkameen.

The area was occupied by Pleistocene glaciation, and a widespread mantle of glacial drift covers the underlying bedrock. At the end of the Pleistocene, marginal lakes formed along the sides of the melting ice lobe and streams deposited their loads in them as deltas and accumulations of silt. These accumulations now form the white cliffs that are particularly prominent along the southern end of Okanagan Lake.

Geographic features include:

The Okanagan has a mild, relatively dry climate that varies depending on latitude. Most of the Okanagan lies within the rain shadow of the Cascade Mountains to the southwest. Areas in the north end of the valley receive more precipitation and cooler temperatures than areas to the south. Generally, Kelowna is the transition zone between the drier south and the wetter north.

The Okanagan north of Kelowna has a humid continental climate (Köppen: Dfb) with warm, sometimes hot summers and cold winters with highs around freezing, though mild by Canadian standards. Precipitation is well distributed year round. Some regions of the Okanagan, most notably near Kelowna, border on an inland oceanic climate due to it having an average temperature slightly above −3.0 °C (26.6 °F) and below 0 °C (32 °F). Dry forests of ponderosa pine and low grasses dominate the valleys and mountains in this region.